Stop watch



Jan. 21, 1936. H- HOFER 2,028,452

STQP WATCH Filed Dec. 26, 1954 Patented Jan. 21, 1936 UNITED STATES PATENT OFFICE STOP WATCH Switzerland Application December 26, 1934, Serial No. 759,305 In Switzerland January 25, 1934 2 Claims.

This invention relates to stop Watches of the type having a chronograph wheel which drives a seconds indicating hand, and a counter wheel which indicates the number of revolutions made by the chronograph Wheel.

Usually in such types of stop watches provision is made oi a pillar Wheel to which a step by step movement can be imparted and which controls a rocking leve-r carrying a driving wheel imparting rotation to the chronograph Wheel. By actuating the pillar wheel, by means of a push rod, said lever can be made to rock so as to engage the driving Wheel with the chronograph wheel or to disengage it therefrom.

In the present invention the wheel which imparts rotation to the chronograph Wheel is mounted on an arbor of the normal time train of the Watch, which arbor is iulcrumed at one of its ends and engaged in the rocking lever at the other end. In this manner it is possible toi disengage the chronograph Wheel from driving engagement by making said arbor swing slightly about its fulcrum, so that the Wheel coacting with the chronograph wheel falls out of mesh with this chronograph Wheel, While the Wheels on this arbor which belong to the normal time train remain in driving engagement With the corresponding wheels of the time train.

It is an object of this invention to provide means for permitting said arbor to swing in a transverse plane but preventing any substantial axial movement of the arbor, independently of the fact that this arbor is engaged in the rocking lever controlled by the pillar Wheel, so that 35 when for any reason the stopping and counting mechanism must be removed from the Watch movement, said arbor remains in its proper position with respect to the time train and to permit removal of the rocking lever Without that the arbor must be removed and the Wheels of the time train run completely down.

In the accompanying drawing, showing a preferred form of embodiment of the invention,

45 Figure l is a plan View of a stop Watch movement according to the invention.

Figure 2 is a section taken along the line 2-2 of Figure 1 and drawn to a larger scale.

The watch movement shown in Fig. 1 is actuated by a main spring lodged in the spring barrel I on the axis 2 of which is mounted a gearl wheel 3 frictionally engaging With the barrel I and meshing with the cannon pinion 4 connected by minute Wheels 5 to the hour Wheel 6 which carries the hour hand. It will be seen that minute and ho r hands are actuated as in usual Roskopf Watch movements.

The gearing of the spring barrel l With a pinion 'I rigid with a gear Wheel 8 which is in mesh with the pinion 9 of the seconds Wheel I0 engaging the pinion II of the escape ment Wheel I2. The stem I3 permits Winding of the main spring and setting of the watch.

A pillar Wheel l5 coacts with a push rod IS slidably mounted in a slot il of the movement plate I8. A spring i@ urges the push rod outwardly which rod, when a push is exerted thereon with the finger makes the pillar Wheel turn through one tooth. A nely toothed chronograph Wheel 20 is disposed as usual in the center of the movement and is rigid With a heart 2| and with a nger 22. rhe counter Wheel 23 is rigid with the hand indicating the number of revolutions of the chronograph wheel, and with a heart 24. The two hearts 2l and 24 coact with a hammer 25 the position of which is controlled by the pillar wheel i5.

A rocking lever 26 is pivoted on the movement plate at 2l and its position is also controlled by the pillar Wheel I5. The rocking lever 26 carries an intermediate gear wheel 2t. meshing with the counter Wheel 23 and coacting with the iinger 22 which imparts a slight movement of rotation to the Wheel 28 at each complete revolution of the chronograph wheel 20. The arbor 29 of the seconds wheel I0 has one end carried by a bridge 3U and the other end by the rocking lever 26. A finely toothed wheel 3lv is rigidly mounted on this shaft near that end thereof which is engaged in the rocking lever. According to the position of the rocking lever, this wheel 3l can be brought in driving engagement with the chronograph wheel 20.

The arbor 29 is provided with a collar 32 intermediate the two wheels it and 3l, and disposed Within an opening 33 of the movement plate. This opening is closed by a plate screwed to the movement plate and provided With an opening 35 for the passage of the arbor 29. This opening 35 has a slightly larger diameter than the arbor, so as to permit a small lateral to-and-fro movement of this arbor corresponding to a slight rocking movement of the lever 26. A spring 36 tends to turn the lever 26 in counterclockwise direction to maintain the wheel 3| in engagement with the center wheel 20. An eccentricJ screw 31 screwing into the movement plate permits exact adjustment of the position of the lever 28 so that it properly coacts with the pillar Wheel I5.

As it is usually the case in stop Watches, the described mechanism can occupy three positions, the rst in which the counting mechanism is running, the second in which the mechanism is stopped, and the third in which the wheels are set back to zero` position.

- The first of these positions is shown in Fig. l of the drawing. The free end oi the lever 2G penetrates between two pillars of the pillar wheel i5 and the wheels Si and 263 mesh with each other, the wheel Si being actuated by the main spring and imparting to the wheel 2B one revolution per minute. After each revolution of this wheel the finger 22 actuates the wheel 28 which turns the wheel 23 through one tooth. A spring 38 yieldingly holds this wheel in its position.

When now a push is exerted on the push rod I6, the pillar wheel i5 turns through a short distance and the lever 25 penetrating in the path of the pillars oi the wheel l5, is pushed in, clockwise direction by one of the pillars and then maintained on top of one of the pillars. Owing to this movement of the lever Z6 the wheel 3l has disengaged from the wheel 2G, since the bearing for the arbor 29 in the lever 25 has moved with the lever, this movement being permitted by the opening 3% in the plate 3d; also the wheel 28 has moved out of the path of the nger 22. The hammer 25 which in the rst position had its edge 353 engaged en top of a pillar of the Wheel i5, is still maintained in this position after the first push on the rod l 6, since the wheel l 5 has not turned far enough to make the edge 39 fall off the pillar. After a second push on the rod i6 the hammer 25 however falls off the pillar and the spring l makes the hammer turn about its pivot l to have the two at edges 42 and 33 act against the hearts 2i and 24, respectively, so that these hearts are urged into a position corresponding to the zero position of the Wheels 20 and 23, respeetively. After the second push on the rod i5 the free end of the lever 28 is still engaged on top of a pillar to maintain the wheel 3i separated from the center wheel 2li, while after a third push, the mechanism is again in running position as represented in Fig. 1.

The plate 35 and the collar 32 on the karbor 2S have the purpose to limit the longitudinal movements of the arbor 29. Owing to this disposition the arbor 2S always keeps its proper position relative to the other members of the wheelwork, even when the rocking lever 26 is removed. When the mechanism is assembled, it is possible to place the arbor 29 in its position before the lever 2d is added, and when any repair work has to be done, the lever can be removed while the arbor remains in its position.

I claim:

l. A spring driven stop watch having a chronograph wheel, a counter wheel indicating the number of revolutions of the chronograph wheel, a driving finger rigid with the chronograph wheel, an intermediate wheel meshing with said counter wheel and actuated by said driving finger, a wheelwork transmitting movement from the driving spring to the chronograph wheel, one of the wheels of said wheelwork being movable into and o'ut of engagement with the chronograph wheel, a rocking lever carrying said intermediate wheel, a fulcrumed arbor carrying said movable Wheel of the wheelwork and having one end journaled in said rocking lever, said rocking lever being movable into one or the other of two positions, an apertured plate traversed by said arbor and disposed intermediate the rocking lever and the iulcrum of the arbor, a collar on said arbor coacting with said plate for preventing substantial axialmovement of the arbor but permitting transverse movement thereof, a pillar wheel coacting with said rocking lever, and means for imparting a step by step movement to said pillar wheel to move said rocking lever into one or the other of its two positions, whereby in one position of the lever said movable wheel engages the chronograph wheel and said intermediate wheel projects into the path of said driving linger, whilst in the other position said movable wheel and said intermediate wheel are removed from the chronograph wheel and from the driving nger, respectively.

2. A spring driven stop watch having a chronograph wheel, a counterwheel indicating the number of revolutions of the chronograph wheel, an intermediate wheel transmitting movement from said chronograph wheel to the counterwheel, a wheelwork transmitting movement from the driving spring to the chronograph wheel, one oi the wheels of said wheelwork being movable into and out of driving engagement with the chronograph wheel, a rocking lever carrying said intermediate Wheel, a fulcrumed arbor carrying said movable wheel of the Wheelwork and having one end journaled in said rocking lever, a collar on said arbor, abutment means coacting with said collar to prevent substantial axial movement of the arbo'r but permitting a limited transverse movement thereof, a pillar wheel coacting with said rocking lever, and means for imparting a step by step movement to said pillar wheel to move said rocking lever into one or the other of two positions, whereby in one position of the lever said movable Wheel engages the chronograph wheel and said intermediate wheel transmits rotation from the chronograph wheel to the counter wheel, whilst in the other position said movable wheel and said intermediate Wheel are removed from driving relation with the chronograph wheel.

HENRI HOFER. 

